Wireless communication systems may be implemented utilizing various access techniques such as, for example, code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), and other multiple access techniques to communicate services such as multimedia services or applications to users over communication channels. A communication channel is characterized by fluctuating signal levels and additive interference from in-cell and outer-cells. Signals transmitted over communication channels may exhibit co-channel interference, path loss, shadowing, and/or multipath fading, which directly affect the communicated signals and result in time-varying signal quality such as time-varying signal to interference plus noise power ratio (SINR).
The use of multiple receive antennas at a wireless terminal has been adopted in various wireless communication systems, including the 3GPP long-term evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX), in order to improve link quality, throughput, mitigate multipath fading. A plurality of antennas enables the subscriber (SS) to reject interference based upon the spatial signature of the interference. Multiple antennas may be used in both uplink and downlink transmission. In a time division duplex (TDD) system, the uplink and downlink channels are reciprocal; hence, a subscriber could exploit the channel knowledge and transmit from a plurality of antennas so as to have the transmissions coherently combine at the base station. This is referred to as beamforming.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.